Category, permalink and re-index

[learn2success]

I am about to do some major change in my site, would that be effect my SEO
My site has almost 150 posts and pages.

1. Moving almost all of the post to new categories and delete the old categories
2. Change the URL (permalink) post name to category / post name
3. Delete my site map from Google web master tool and re-index them (is it a good practice ?)

Your advice and time is much appreciated.

Regards,
NJ

[HTMLBasicTutor]

When you delete the old categories - 301 permanent redirect them to another similar category or the home page. i.e. don't loose the incoming links you don't know about

The same thing is required when you change your permalinks. If the permalink structure is already just the post name, I would personally leave it as is.

[C.Rebecca]

@ 3.. Whats the point of deleting the old Sitemap and resubmitting it?
What if some of your pages could not get indexed this time... Its better to ping rather deleting it.

[webcosmo]

301 is the best thing you can do.

your #3 point is good if you already have uploaded one.